Electrical feedthrough assemblies for containment structures having specially controlled environments

ABSTRACT

An electrical feedthrough assembly for a containment structure having a specially controlled environment. The feedthrough assembly is designed to provide desired electrical performance while maintaining the integrity of the controlled environment of the containment structure under both normal and emergency conditions. The feedthrough assembly includes one or more header plates having removably mounted and redundantly sealed feedthrough modules provided therein with provision being made for internal manifolding so as to permit continuous pressure testing of the integrity of the module seals. Each feedthrough module has a construction which provides substantially rigid electrical and mechanical coupling between input and output conductors so as to eliminate the need for insulated wires within the assembly.

Sorensen atent 1 1 1 Apr. 9, 1974 [75] inventor: David 1111. Sorensen, Westlake Village, Calif.

[73] Assignee: Bunker Ramp Corporation, 0ak

Brook, lll.

[22] Filed: Sept. 23, 11.971

[21] Appl. No.: 183,186

[52] US. Cl. 339/611) M, 174/151, 339/94 A, 339/113 R [51] int. Cl .Q. H0111 7/02 [58] Field of Search..... 339/60 R, 60 M, 94, 113 R, 339/129; 285/93, 137 R, DIG. 18; 174/151, 11 R; 277/26; 176/87 [56] References Cited UNITED STATES PATENTS 3,022,484 2/1962 Thompson 339/94 M FOREIGN PATENTS OR APPLlCATlONS 712,786 7/1954 Great Britain 285/D1G. 18

Primary Examiner-Marvin A. Champion Assistant Examiner-William F Pate, Ill

Attorney, Agent, or Firml\lathan Cass; F. M. Arbuckle 5 7 ABSTRACT An electrical feedthrough assembly for a containment structure having a specially controlled environment. The feedthrough assembly is designed to provide desired electrical performance while maintaining the integrity of the controlled environment of the containmentstructure under both normal and emergency conditions. The feedthrough assembly includes one or more header plates having removably mounted and redundantly sealed feedthrough modules provided therein with provision being made for internal manifolding so as to permit continuous pressure testing of the integrity of the module seals. Each feedthrough module has a construction which provides substantially rigid electrical and mechanical coupling between input and output conductors so as to eliminate the need for insulated wires within the assembly.

10 Claims, 8 Drawing Figures JATENTEOAPR 91974 3303.531

sum 3 HF a 04 W0 K. SORENSE/V ELECTRI CAL FEEID'IIIIROIJGll-I ASSEMBLIES FOR CGNTAINIVIIIN'I STRIJQ'IIJRIES HAVING SIPIECIALILII CUN'IROILLIEID ENVIRONMENTS BACKGROUND OF THE INVENTION The providing of electrical feedthrough connections to devices within a containment structure requiring a specially controlled environment has present4d considerably difficulties in the art, since such connections must be provided in a manner so as not to affect or interfere with the maintenance of the integrity of the environment within the containment structure. Such containment structures may, for example, be those associated with nuclear reactors, hot cells, radiation laboratories, marine applications and fuel reprocessing facilities. An appreciation of the stringent requirements which such electrical connections may have to meet will be obtained by noting that, under emergency conditions, an electrical feedthrough assembly for a nuclear reactor may have to withstand pressures and temperatures as high as 1,250 PSIG and 600 F, respectively, as well as extreme levels of radiation.

SUMMARY OF THE INVENTION It is accordingly a broad object of the present invention to provide improved electrical feedthrough assemblies for a containment structure having a specially controlled environment.

A more specific object of the invention is to provide an improved electrical feedthrough assembly for a nuclear reactor containment structure which is able to provide desired electrical performance while maintaining the integrity of the containment environment under both normal and emergency conditions.

Another object of the invention is to provide an electrical feedthrough assembly for a containment structure which eliminates the need for insulated wires within the assembly.

A further object of the invention is to provide an electrical feedthrough assembly for a containment structure which can be factory-assembled and fieldinstalled with minimum effort.

Still further objects of the invention are to provide an improved electrical feedthrough assembly for a containment structure which additionally provides superior heat transfer, modular construction, high conduc tor density, conductor modular replaceability and interchangeability, constant leak detection capability, compact size for faster leak detection, field serviceability and ease of handling, greater integrity, economy of design, and versatility on upgrading existing services.

In accordance with exemplary embodiments of the present invention, compact electrical feedthrough assemblies are provided for attachment to a containment structure. In one exemplary embodiment, a single header feedthrough assembly is provided having removably mounted and redundantly sealed electrical feedthrough module constructions with internal manifolding being provided to permit continuous pressure testing of the integrity of the module seals. In a second exemplary embodiment, a mated double header construction is employed in which redundantly sealed feedthrough conductor module constructions are provided in two adjacent headers with an interfacial seal between them, the space between the two headers being used to permit continual pressure testing of the integrity of the module seals. In both embodiments each feedthrough conductor module construction provides substantially rigid electrical and mechanical coupling between input and output conductors and also is individually removable and interchangeable so as to permit replacement without affecting the integrity of the containment structure or otherwise interrupting service in the other conductor modules.

The specific nature of the invention as well as other features of construction and further advantages, uses and applications thereof will become apparent from the following detailed description of the abovesummarized embodiments taken in conjunction with the accompanying drawings in which:

FIG. I is a perspective view of a single header electrical feedthrough assembly in accordance with the invention, a sector portion being cut-away to show the internal construction, and portions of the feedthrough module and attached cable being shown in exploded fashion.

FIG. 2 is a cross-sectional view of an exemplary embodiment of a feedthrough module construction which may be employed in the single header assembly of FIG. I.

FIG. 3 is a cross-sectional view of a modified version of the feedthrough module construction of FIG. 2.

FIG. 41 is a fragmentary cross-sectional view illustrating details of the redundantly sealed mounting em ployed for a feedthrough module construction in the single header assembly of FIG. 1.

FIG. 5 is a cross-sectional view illustrating how a blind flange may be provided as a termination for a feedthrough module construction.

FIG. 6 is a perspective view of a mated double header electrical feedthrough assembly in accordance with the invention with a sector portion cut-away to show the internal construction.

FIG. 7 is a cross-sectional view of an exemplary embodiment of a feedthrough module construction which may be employed in the mated double header assembly of FIG. 6.

FIG. 8 is a fragmentary cross-sectional view illustrating details of the redundantly sealed mounting con struction employed for a feedthrough module construc tion in the mated double header assembly of FIG. 6.

Like numerals designate like elements throughout the figures of the drawings. To facilitate understanding of the invention, elements of the header are designated by numbers less than and elements of the feedthrough module construction and attachments are designated by numbers greater than I00.

Referring initially to the exemplary single header assembly illustrated in FIG. II, a single cylindrical header plate I0 is provided having mounting holes III for mounting the header plate 10 to a welding neck flange on a steel pipe or nozzle (not shown) typically provided on a containment structure for receiving electrical feedthrough connections. Circular O-ring grooves I4 are provided in the header plate for sealing therebetween. Mounting of the header plate 10 to the containment structure could also be accomplished by welding if so desired.

As illustrated in FIGS. I and 2, the header plate llt) contains feedthrough holes I2 in which feedthrough module constructions III) are mounted. Each feedthrough module construction 110 typically includes abutting cylindrical interfacial resilient grommets lllll and 113 (e.g., silicon rubber) having interfacial conductive contacts 115 suitably provided therein. The opposite ends of these interfacial contacts 115' respectively receive, in mechanical and electrical engagement, the mating terminals 117 and 137 of receptacle and cable module terminations 119 and 139 between which electrical feedthrough connections are to be provided. As will be evident from FIG. 1, a module termination may be either a receptacle termination 119 or a cable termination 139. For example, FIG. 3 illustrates an exemplary feedthrough module constructon having two receptacle terminations 119.

Considering first the receptacle termination 119 at the right end of the module construction (as viewed in FIG. 2), it will be seen that the receptacle termination 119 may typically comprise a grid plate 120 having a depending cylindrical shell 121 at its outward end and a mounting flange 122 at its inward end. The terminals 117 of the receptacle termination 119 are hermetically sealed within the grid plate 120, such as by being fused with glass beads 123 to provide a hard hermetic seal. The outward shell 121 (see also FIG. 1) is externally threaded to permit attachment of a mating connector of a cable (not shown) in a conventional manner. The grid plate 120 is bolted to the header plate by module mounting bolts 126 passing through holes 124 in the flange 122 and threaded in holes 16 of the header plate 10.

As shown in detail in FIG. 4, a C-shaped selfenergizing bi-metallic sealing ring 130 is disposed in a corresponding recess 13 of the header plate 10 to provide a high quality seal for the feedthrough module. This sealing ring 130 may typically be made of stainless steel plated with a soft metal such as silver, indium or lead so that, after being applied using pressure and heat, its soft plating surface deforms onto the mating surfaces to provide a high degree of sealing. As will also be evident from FIG. 4, redundant sealing is provided by appropriately finishing the abutting seating surfaces 131 of the flange 122 and header plate 10, thereby providing two sealing surfaces in series so as to further increase the reliability and quality of the resulting module sealing. In the event that it is desired not to use a particular feedthrough module location, a blind flange 132 may be employed and sealed in a like manner, as illustrated in FIG. 5.

Considering now the cable termination 139 provided at the left end of the module construction (as viewed in FIG. 2), it may typically include a grid plate 140 having a flange 142 with holes 144 so as to permit mounting and redundant sealing to the header 10 using a sealing ring 130 in a corresponding header plate groove 13 in a like manner as described for the receptacle grid plate 120. The terminals 137 of the grid plate 140 are likewise hermetically sealed therein by being fused with glass beads 143 to provide a hard hermetic seal. The grid plate terminals 137 mate with respective contacts 156 of an attaching cable 150, and is preferably permanently affixed thereto by potting material 151 within the cable potting boot 152.

In order to permit continual pressure testing of the integrity of the module seals, internal manifolding is advantageously provided for the assembly of FIG. 1 by the provision of communicating grooves (FIG. 1) in the header plate 10 which interconnect the feedthrough holes 12 for common communication with an access hole 20 in which a pressure gage 2S and associated valve assembly are suitably mounted.

Referring next to FIGS. 6-8, illustrated therein is a second exemplary embodiment of the invention employing a mated double header construction instead of the single header construction illustrated in FIG. 1. As shown in FIG. 6, adjacent header plates and 62 are bolted together using double-ended studs 64 passing through corresponding holes 61 provided therein. The header plates 60 and 62 include abutting flange portions 60a and 62a with a gasket flange seal 66 therebetween to seal off the interfacial opening. The mated double header assembly is illustrated in FIG. 6 as being welded to the nozzle or steel pipe of a containment structure, but could also be provided for mounting by bolting to a welding neck flange similarly to that shown for the single header assembly in FIG. 1.

As illustrated in FIGS. 6 and 7, the header plates 60 and 62 are provided with aligned feedthrough holes 67 and 69 in which feedthrough module constructions 160 are mounted. As best shown in FIG. 7, each feedthrough module construction 160 typically includes grid plates 172 and 182 bolted to respective header plates 60 and 62 by bolts 173 and 183 which pass through holes in respective grid plate flanges 174 and 184 and are threaded in respective holes 63 and 65. The grid plates 172 and 182 have terminals 177 and 187 mechanically and electrically engaging opposite ends of interfacial contacts 165 disposed within an interfacial rubber grommet 161. These grid plate terminals 177 and 187 are hermetically sealed with glass beads I78 and 188 so as to provide a hard seal in a like manner as described for the grid plate terminals in the single header embodiment of FIGS. 1 and 2. Also, similar to the grid plate in the single header embodiment, the double header grid plate 172 has a threaded outwardly depending cylindrical shell 179 so as to provide a receptacle termination for receiving a mating cable connector (not shown); and, also similar to the grid plate 142 in the single header embodiment, the other double header grid plate 182 provides a cable termination with its terminals 187 mating with respective terminals 197 of an attaching cable 190, and is preferably permanently afiixed thereto by potting material 191 within the cable potting boot 192.

As will be evident from FIG. 8, the double header grid flanges 172 and 182 also employ high performance seals in a similar manner as in the single header embodiment as well as providing redundant sealing by appropriately finishing the abutting sealing surfaces 199. FIG. 8 further illustrates how even greater redundancy may be provided by using a compressible gasket seal 200 between the grid plate flange 174 and the header plate 60. Continual pressure testing of the module seals in the mated double header embodiment is accomplished, as illustrated in FIG. 6, using an access hole 68 provided in header plate 62.

Although the invention has been described herein with respect to particular exemplary embodiments, it is to be understood that various modifications in construction, arrangement, and/or use may be made within the scope of the invention as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An electrical feedthrough assembly for a containment structure having a controlled environment comprising:

header means cooperatively mountable to said containment structure for feeding electrical connections to the interior thereof,

said header means including at least one feedthrough module, conductor-receiving terminations at opposite ends of said module for respectively receiving conductors from inside and outside of said containment structure, each conductor-receiving termination including an insulative member supporting at least one hermetically sealed electrical terminal therein,

said feedthrough module having interfacial means comprising an insulating member supporting at least one interfacial electrical contact for removable engagement with the terminals of said conductor-receiving terminations so as to provide substantially rigid electrical and mechanical coupling therebetween, means for removably mounting each conductorreceiving termination to said header means, and

sealing means provided between said header means and said conductor receiving terminations at first and second spaced locations chosen so that removal of only one of said conductor-receiving terminations will not affect the sealing integrity of said containment structure.

2. The invention in accordance with claim 1, wherein said header means comprises a single plate having a module receiving opening for receiving said module.

3. The invention in accordance with claim 1, wherein said header means comprises first and second adjacent header plates having aligned module receiving openings for receiving said module wherein one of said conductor-receiving terminations is removably mounted to each header plate, and

wherein each header plate contains one of said first and second locations of said sealing means.

4. The invention in accordance with claim 1, wherein said sealing means includes at least one self-energizing bi-metallic sealing member disposed between said header means and said module.

5. The invention in accordance with claim 4, wherein said sealing means provides for additional sealing by appropriately finishing predetermined abutting header and module seating surfaces spaced from bi-metallic sealing member.

6. The invention in accordance with claim 4, wherein said sealing means provides for additional sealing by the provision of at least one compressible gasket seal between said module and header means at a location spaced from said bi-metallic sealing member.

7. The invention in accordance with claim 1, wherein said header means and said module having a construction so as to provide an access opening to said module at a location between said first and second locations for monitoring the integrity of said sealing means.

8. The invention in accordance with claim 7, wherein at least one additional feedthrough module of like construction and arrangement is similarly mounted within said header means, and wherein said header means has a construction which provides common communication between the module access openings so as to thereby provide for simultaneous pressure testing of the sealing means of the modules.

9. The invention in accordance with claim 8, wherein said header means comprises a single header plate having module openings therein for respectively receiving a plurality of said modules, and wherein said common communication is provided by grooves interconnecting said module openings.

10. The invention in accordance with claim 8, wherein said header means comprises first and second adjacent header plates with said sealing means being located to provide a sealed interfacial opening therebetween, said header plates having a plurality of aligned module openings for receiving respective ones of said modules, said interfacial opening communicating with each module opening so as to permit simultaneous pressure testing of the module sealing.

l 1 =1 i i 

1. An electrical feedthrough assembly for a containment structure having a controlled environment comprising: header means cooperatively mountable to said containment structure for feeding electrical connections to the interior thereof, said header means including at least one feedthrough module, conductor-receiving terminations at opposite ends of said module for respectively receiving conductors from inside and outside of said containment structure, each conductor-receiving termination including an insulative member supporting at least one hermetically sealed electrical terminal therein, said feedthrough module having interfacial means comprising an insulating member supporting at least one interfacial electrical contact for removable engagement with the terminals of said conductor-receiving terminations so as to provide substantially rigid electrical and mechanical coupling therebetween, means for removably mounting each conductor-receiving termination to said header means, and sealing means provided between said header means and said conductor receiving terminations at first and second spaced locations chosen so that removal of only oNe of said conductorreceiving terminations will not affect the sealing integrity of said containment structure.
 2. The invention in accordance with claim 1, wherein said header means comprises a single plate having a module receiving opening for receiving said module.
 3. The invention in accordance with claim 1, wherein said header means comprises first and second adjacent header plates having aligned module receiving openings for receiving said module wherein one of said conductor-receiving terminations is removably mounted to each header plate, and wherein each header plate contains one of said first and second locations of said sealing means.
 4. The invention in accordance with claim 1, wherein said sealing means includes at least one self-energizing bi-metallic sealing member disposed between said header means and said module.
 5. The invention in accordance with claim 4, wherein said sealing means provides for additional sealing by appropriately finishing predetermined abutting header and module seating surfaces spaced from bi-metallic sealing member.
 6. The invention in accordance with claim 4, wherein said sealing means provides for additional sealing by the provision of at least one compressible gasket seal between said module and header means at a location spaced from said bi-metallic sealing member.
 7. The invention in accordance with claim 1, wherein said header means and said module have a construction so as to provide an access opening to said module at a location between said first and second locations for monitoring the integrity of said sealing means.
 8. The invention in accordance with claim 7, wherein at least one additional feedthrough module of like construction and arrangement is similarly mounted within said header means, and wherein said header means has a construction which provides common communication between the module access openings so as to thereby provide for simultaneous pressure testing of the sealing means of the modules.
 9. The invention in accordance with claim 8, wherein said header means comprises a single header plate having module openings therein for respectively receiving a plurality of said modules, and wherein said common communication is provided by grooves interconnecting said module openings.
 10. The invention in accordance with claim 8, wherein said header means comprises first and second adjacent header plates with said sealing means being located to provide a sealed interfacial opening therebetween, said header plates having a plurality of aligned module openings for receiving respective ones of said modules, said interfacial opening communicating with each module opening so as to permit simultaneous pressure testing of the module sealing. 